Adjustable rotary speed responsive switch



Och 1956 J. K. GAYLORD ETAL 2,766,347

ADJUSTABLE ROTARY SPEED RESPONSIVE SWITCH Filed April 1, 1954 UnitedStates Patent ADJUSTABLE ROTARY SPEED RESPONSIVE SWITCH James K. Gaylordand Paul T. Hahn, Chicago, 111., assignors to Gaylord Products,Incorporated, Chicago, 11]., a corporation of Delaware Application April1, 1954, Serial No. 420,324

4 Claims. (Cl. 200-80) This invention relates to improvements in arotary speed responsive switch and refers particularly to an electricswitch which will make and break an electric circuit in response todifierent rotary speeds of a rotating body.

One of the important features of the present invention resides in theprovision of an electric switch which can be made to close an electriccircuit in response to a predetermined rotary speed of a body and toopen the switch at a different predetermined speed of rotation, therotation proceeding in the same direction, or the device may be maderesponsive to close a circuit in response to a predetermined rotationalspeed in one direction and opens the circuit in response to apredetermined rotational speed in the opposite direction.

Another important feature of the invention resides in a switch which isresponsive to the rotational speed of a body, as heretofore described,wherein the responsive rotational speed of closing and opening of thecircuit, with rotation proceeding in either direction, can be quicklyand conveniently changed over a wide range of rotational speeds.

A further'important feature of the invention resides in a switch, of thecharacter described, which opens and closes with the rapidity necessaryto avoid excess arcing at the switch points.

Other objects and advantages of the invention will be apparent from theaccompanying drawing and following detailed description.

In the drawing,

Fig. 1 is a sectional View taken through an embodiment of the presentinvention.

Fig. 2 is a transverse sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. 1,showing the switch in open position.

Fig. 4 is a sectional view similar to that shown in Fig. 3, illustratingthe switch in closed position.

Although the present invention may be used in substantially anyenvironment to control substantially any type electrical circuit inresponse to the rotational speed of any rotating body, for purposes ofillustration the invention will be described in conjunction with anautomobile tocontrol an electric circuit associated with the automobile,the control being exercised in response to the movement of theautomobile. To conveniently control the desired electrical circuit inresponse to the movement of the automobile the speedometer cable, whichmoves in proportion to the movement of the automobile, will be employedas the controlling rotating body.

Referring in detail to the drawing, 1 indicates generally an embodimentof the present invention. The dev ce 1 comprises a cup-shaped container2 WhICh IS open at its upper end and which may be closed by asuitableclosure 3. The container 2 is preferably circular in section andhas a circular outer wall 4 and a bottom 5. A tubular extension 6,preferably formed integral with the container bottom, extends upwardlyfrom the bottom where- 2,766,347 Patented Oct. 9, 1956 by an annularcompartment 7 is provided within the container. In utilizing the device,an electrically non-conductive liquid 8 is carried in the container.

The container 2 is preferably constructed of an electrical insulatingmaterial such as plastic, fiber, hard rubber or the like. The closure 3comprises a circular disc portion 9 which, when the device is assembled,rests upon the upper edge of the annular wall 4 and may be sealedthereto as shown at 10 in Fig. l.

A boss 11 extends downwardly from the bottom 5 and is preferably formedintegral with said bottom, said boss being provided with a relativelyenlarged bore 12 which is adapted to receive an end portion 13 of aspeedometer cable sheath, the speedometer cable sheath embracing aconventional speedometer cable 14. The disc portion 9 of the closure 3also carries an upwardly extending boss 15 similar to the boss 11, boss15 being preferably integral with the disc 9. The boss 15 is providedwith a bore 16 for the reception of a spaced end portion of thespeedometer cable sheath, said end portion being designated by thereference numeral 17.

Both the boss 11 and boss 15 are provided with relatively restrictedbores 18 and 19 respectively through which the cable 14 passes, saidcable extending through the tubular extension 6 within the container 2.

A sleeve 20 is rotatably positioned in the hollow bore of the extension6, said sleeve circumscribing the speedometer cable 14 and being spacedtherefrom. A resilient friction gripping member 21 is positioned betweenthe speedometer cable 14 and the upper end portion of the sleeve 20 andfrictionally connects the speedometer cable to sleeve 20 wherebyrotation of the speedometer cable causes sleeve 20 to rotate within thehollow bore of the projection 6. A spider 22 embraces the upper endportion of the sleeve 20 and carries a cap 23 which is rigidly mountedupon the sleeve 20. The spider 22 carries downwardly and outwardlyextending arms 24 which are secured adjacent their end portions to ahollow semitoroidal driving rotor 25. The arrangement is such that whenthe speedometer cable 14 rotates the driving rotor 25 will be rotated.By virtue of the shape of the arms 24 the rotation of the driving rotor25 will take place within the liquid 8 carried within the container 2.

A hollow semi-toroidal driven rotor 26 is positioned beneath the drivingrotor 25, said driven rotor 26 comprising a hub 27 which is rotatablyjournalled upon the lower portion of the tubular extension 6. The drivenrotor 26, being beneath the driving rotor 25 is, of course, alsoimmersed within the body of liquid 8.

The rotors 25 and 26 are of the same general construction which isemployed in hydraulic torque converters for power transmission purposesparticularly in automotive vehicles. Each of the rotors 25, as has beenhereinbefore described, is of hollow construction and the semi-toroidalspaces defined by the walls of the rotors are divided by a plurality ofcircumferentially spaced partitions 28 and 29, being the partitions ofthe rotor 25 and 26 respectively. Thus, the interiors of the rotors 25and 26 are divided into a plurality of radial compartments, thecompartments of the respective rotors facing each other.

The arrangement is such that when the driving rotor 25 is rotated by thespeedometer cable 14 a torque will be exerted upon the driven rotor 26.As has been hereinbefore described the driven rotor 26 is freelyrotatable upon the lower portion of the tubular extension 6. However, aswill be hereinafter more fully described, the torque exerted upon thedriven rotor 26 is resisted resiliently and consequently the rotationalmovement of the driven rotor 26 is relatively restricted.

A resilient frame 30 is positioned within the container 2 adjacent thebottom portion thereof. The frame 30 comprises a side 31 which isrigidly secured to the Wall 4 of the container 2 by means of rivets orthe like 32. The frame 3% also comprises a side 33 which is integrallyjoined to side 31, the side 33 extending at an angle to the side 31. Atthe opposite end of the side 33 a side 34 is formed, said side beingintegrally connected to side 33. An anchorage portion 35 also comprisesa portion of frame 30, said anchorage portion extending from the side 31and being formed integral therewith. The frame 31) is preferably formedof spring steel and the various sides, hereinbefore described, may beformed by appropriately bending the steel strip from which the frame isformed.

Intermediate the length of the side 34 of frame 30 a U-shaped loop 36 isformed. The driven rotor 26, adjacent its outer periphery, carries adownwardly extending lug 37 which extends into the loop 36. Thus, thetorque exerted upon the driven rotor 26 by the driving rotor 25 isresisted by the engagement of the lug 37 in loop 36, that is, saidtorque is resiliently resisted by the frame 30.

The side Wall 4 of the container 2 is provided with an internallythreaded aperture 38 which is adapted to receive a threaded plug 39. Oneend of the plug 39 is relatively restricted in diameter to form "aswitch contact point 40 which extends inwardly into the compartment 7.The anchorage member 35 of the frame 30, adjacent its end, extends at anangle to itself to form an anchorage lug 41. The lug 41 is provided withan aperture or slot in which an end portion 42 of a movable contact arm43 is pivotally positioned. The movable contact arm carries a switchcontact point 44 which is positioned adjacent the contact point 40, thecontact point 44 being movable toward and away from the contact point 40to make and break an electrical circuit. The movable contact supportingarm 43 is bent at an angle adjacent its end to form a toggle supportinglug 45. The lug 45 is provided with an aperture for the reception of anend portion 46 of a toggle link 47, the opposite end portion 48 of saidlink engaging in an aperture provided in the end portion of side 34 offrame 30. As will be hereinafter more fully described the assemblycomprising the movable contact supporting arm 43 and the toggle link 47comprises a toggle mechanism whereby the switch points 40 and 44 may bebrought together or separated rapidly, that is, the contact 44 snapsinto electrical contact with the contact 40 when the switch is closedand snaps away from the contact 40 when the switch is open. Thus theelectrical circuit which may be associated with the contacts 40 and 44may be made or broken rapidly inhibiting arcing at the contact points.

The engagement of the toggle link 47 with the side 34 and lug 45 is suchthat the link is pivotally associated with each of said members and alsohas a degree of freedom along its length, that is, the end portions 46and 48 are of less width than the remaining body portion of the link andextend loosely into the apertures provided in lug 45 and side 34,respectively. The same arrangement exists between the end 42 of the arm43 and lu 42.

ln operation, when the driving rotor 25 exerts a torque upon the drivenrotor 26, a thrust is exerted upon the side 34 of the resilient frame 30tending to move sa d side along substantially the direction of itslength. This thrust is resiliently resisted by the frame 30 and resultsin movement of the toggle linkag comprising arm 43 and link 47. Theresilient resistance of frame 30 may be changed by adjusting screw 49which is threadedly positioned in an aperture 50 provided in wall 4. Thescrew 49 has a contact end 51 which may be brought to bear upon side 33of frame 30 whereby the resilience of said side may be varied by themanipulation of the screw 49.

For example, for a predetermined setting of screw 49, the frame may bedisposed, as shown in Fig. 3, that is, the switch points 40 and 44 areseparated. When the points 40 and 44 are separated, the link 47 will bein an inclined position between lug 45 and side 34. In the normalsetting of the frame 30 and toggle linkag comprising arm 43 and link 47,side 34 will exert a compressive stress lengthwise of link 47. Thisstress will tend to rock arm 43 about its pivotal connection with lug41, and when the link 47 is on the side shown in Fig. 3 of its centerposition, this rocking action of arm 43 will take place in a clockwisedirection. To prevent excessive rocking movement of arm 43 in thisdirection, a stop lug 52 positioned upon the base of the extension 6contacts an intermediate portion of arm 43 thereby limiting suchclockwise movement of the toggle linkage.

In the position of the parts, hereinbefore described, it is assumed thatthe cable 14 is stationary and, hence, no torque is exerted upon therotor 26. Accordingly, the contacts 40 and 44 are held apart by thenormal tension of the frame and toggle linkage, the latter beingrestrained by the stop 52.

If the cable 14 is now rotated in the direction indicated by the arrow53 in Fig. 4, a torque will be exerted upon the driven rotor 26 and athrust will be exerted upon side 34 in the direction indicated by thearrow 54 in Fig. 4. This thrust will be resisted by frame 30,principally by side 33 thereof which will tend to flex. Hence, side 34moving in the direction of arrow 54 moves the end 48 of the link 47 inthe same general direction. By virtue of the stop 52 the opposite end 46of link 47 will remain stationary and thus link 47 will pivot about lug45 in a clockwise direction, as viewed in Fig. 4.

The torque exerted upon the driven rotor 26 is proportional to the rateof rotation of the driving rotor 25. Hence, if the driving rotor 25rotates at a predetermined speed, sufficiently great to cause side 34 tomove link 47 to its center position, that is, a horizontal position asviewed in Figs. 3 and 4, the link 47 will be in an unstable position andhence a slight increase in torque will cause the link 47 to move arm 43to the position shown in Fig. 4 wherein contacts 40 and 44 are together.When the link 47 is in its center position the bending stress upon theside 34 is at its maximum, that is, the compression exerted upon thelink 47 is at its maximum. Hence, when the link 47 passes said centerposition due to the thrust exerted upon the side 34, the arm 43 willmove rapidly to the position shown in Fig. 4. This rapid movement isoccasioned substantially by the flexing of the side 34.

Hence, at a predetermined speed of rotation of the cable '14 an electriccircuit which may include contacts 40 and 44 which may be in normallyspaced position, will be closed.

As has been hereinbefore described, the movement of side 34 in thedirection of the arrow '54 is dependent upon the thrust exerted upon thedriven rotor 26. This movement of side 34 is also dependent upon theresistance to such movement offered by side 33. Hence, for apredetermined speed of rotation of cable '14 the side 34 will be movedso as to cause the contacts 40 and 44 to close. By the propermanipulation of the adjusting screw 49 the side '33 can be made to offera greater or lesser resistance to movement of the side 34. Hence, bymoving screw 49 inwardly with respect to the wall 4 the side 33 can, ineffect, be stiffened, that is, it can be made to offer greater resilientresistance to the thrust exerted by the driven rotor 26. Hence, thecontacts =40 and '44 will not close until a greater speed of rotation ofthe cable 14 occurs. The screw 49 may be referred to as a high speedadjustment, that is, its manipulation will determine the maximum speedof cable 14 at which the contacts will close.

*If the cable 14 now slows down, the resistance of the frame 30,principally the side 33, will tend to move the end 48 of the link 47downwardly as viewed in Figs. 3 and 4. In other words, the side 34 willmove in a direction contrary to arrow '54. In view of the fact thatcontact 44 abuts contact 40' the opposite end '46 of link 47 will remainstationary and hence link 47 will pivot in a counterclockwise directionabout lug 45 as viewed in Fig. 4. if the cable 14 slows down to apredetermined degree of rotation the link 47 will eventually move to itsunstable center position. Thereafter, a slight decrease in speed ofcable 14 will cause arm 43 to rock in a clockwise direction about lug 41thereby separating contact 4-4 from contact 40 and opening theelectrical circuit which includes said contacts.

The time at which contact 44 separates from contact 40 depends upon theadjustment of screw 39. For instance, if it is desired to have contacts44 and 40 separate when the cable 1-4 has slowed down a relatively smallamount from its maximum speed, the screw '39 will be moved inwardlyrelative to the wall 4. 'If on the other hand, it is desired that thecontacts separate only after a relatively large decrease of speed frommaximum, the adjustment of screw 39 will be such as to move said screwoutwardly relative to the wall 4. The screw 39 may be referred to as thelow speed adjusting screw since its position determines at whatpredetermined speed of cable 14 the contacts will separate after thecable slows down from its maximum speed. Accordingly, it can readily beseen that by the proper adjustment of screws 49 and G9 the electriccircuit can be closed and opened at substantially any desired range ofdifferential speeds. In other words, the screw 49 may be so adjusted asto cause the circuit to be completed only when a relatively high speedis reached and the screw 39 may be so adjusted as to cause the circuitto be broken when the speed drops off a relatively small degree or bythe proper manipulation of screw 39 the circuit may be caused to bebroken only if the speed has decreased a relatively great amout fromthat at which the circuit was made.

In order to prevent an excessively high torque being applied to thedriven rotor 26, after the contacts 40 and 44 close, bleed openings 55may be provided in the wall of the driving rotor 25. Hence, whensuflicient torque has been exerted upon the driven rotor 26 to cause thecontacts to close, any increase in the pressure of the fluid couplingbetween the driving and driven rotors will be relieved 'by passage offluid outwardly through the openings 55. An opening 55 may be providedinto each of the compartments defined by the radial walls 28.

In order to conveniently connect the contacts 40 and 44 to an externalcircuit a jack 56 may be secured to the outer surface of the wall 4,said jack being carried by a bus bar 57 which may be connected throughthe wall 4 by means of rivets 58 to a jumper bar 59 which in turn may bein electrical connection with contact 40. Similarly a jack 60 carried bybus bar 61 may connect through rivet 32 to the frame 30 which carriesthe contact 44, the contact being grounded upon said frame. Thus, theswitch may be conveniently connected to a desired electrical circuit(not shown).

In the example of the operation of the device '1, hereinbefore setforth, the same direction of rotation of the cable 14 was assumed. Inview of the fact that the toggle linkage comprising arm 43 and link 47is stable in either the circuit-open or circuit-closed position it ispossible to close the circuit at a predetermined speed .in one directionand open the circuit at a predetermined speed of the cable in theopposite direction.

By the provision of the high speed adjusting screw 49 and the low speedadjusting screw 39 the switch can be caused to open or close theelectric circuit at any speeds throughout the full range of speed of thecable and the opening and closing speeds may be selected with a smalldifferential or a large differential, as desired. For instance if topspeed of cable 14 is 100 revolutions per minute, the switch may be soadjusted as to close the electric circuit at, for instance, 90revolutions per minute and open the circuit when the cable slows down to80 revolutions per minute, that is, with a differential of l 6revolutions per minute. However, using the same differential, theclosing speed may be selected at 50 revolutions Per minute. nd theopening speed at 40 revolutions per minute, or closing speed may be 15and opening may be 5. In addition, the differential may be relativelygreat, for instance, the switch may be so adjusted as to close atrevolutions per minute and open at 10 revolutions or the closing of theswitch may be set at any speed within the positive range of speed of thecable and may open at any opposite rotational speed.

Of course, the examples set forth herein are merely for the purpose ofillustrating the flexibility of operation of the device and are notintended as a limitation of the invention.

We claim as our invention:

"1. A rotary speed responsive electric switch which comprises incombination, a container for carrying an electrically non-conductivefluid, a fluid coupled driving rotor and driven rotor immersed in saidfluid, means for rotating said driving rotor to exert a torque upon saiddriven rotor, a resilient frame of predetermined stiffness carried insaid container, means connecting said driven rotor to said frame to flexsaid frame when torque is exerted upon said driven rotor, a togglemechanism connected to said frame, said toggle mechanism having amovable arm, a switch contact point carried by said movable arm, astationary juxtaposed companion switch contact point carried within saidcontainer whereby predetermined rotation speeds of said driving rotorcauses said movable arm to close and open said contact points, meanscarried by said container for changing the stiffness of said resilientframe to change the movement of said arm relative to the rotary speed ofsaid driving rotor, and means for changing the position of saidstationary contact relative to the contact carried by said arm to changethe responsive speed at which the contacts open.

2. A rotary speed responsive electric switch which comprises incombination, a container for carrying an electrically non-conductivefluid, a fluid coupled driving rotor and driven rotor immersed in saidfluid, means for rotating said driving rotor to exert a torque upon saiddriven rotor, a resilient frame of predetermined stiffness carried insaid container, means connecting said driven rotor to said frame to flexsaid frame when torque is exerted upon said driven rotor, a togglemechanism connected to said frame, said toggle mechanism having amovable arm, a switch contact point carried by said movable arm, astationary juxtaposed companion switch contact point carried within saidcontainer whereby predetermined rotation speeds of said driving rotorcauses said movable arm to close and open said contact points, and meanscarried by said container for changing the stiffness of said resilientframe to change the movement of said arm relative to the rotary speed ofsaid driving rotor.

3. A rotary speed responsive electric switch which comprises incombination, a container for carrying an electrically non-conductivefluid, a fluid coupled driving rotor and driven rotor immersed in saidfluid, means for rotating said driving rotor to exert a torque upon saiddriven rotor, a resilient frame of predetermined stiffness carried insaid container, means connecting said driven rotor to said frame to flexsaid frame when torque is exerted upon said driven rotor, a togglemechanism connected to said frame, said toggle mechanism having amovable arm, a switch contact point carried by said movable arm, astationary juxtaposed companion switch contact point carried within saidcontainer whereby predetermined rotation speeds of said driving rotorcauses said movable arm to close and open said contact points, and meansfor changing the stiffness of said frame to change the responsive speedat which the contacts close.

4. A rotary speed responsive electric switch which comprises incombination, a container for carrying an electrically non-conductivefluid, a fluid coupled driving rotor and driven rotor immersed in saidfluid, means for 7 rotating said driving rotor to exert a torque uponsaid driven rotor, a resilient frame of predetermined stifiness carriedin said container, means connecting said driven rotor to said frame toflex said frame when torque is exerted upon said driven rotor, a togglemechanism connected to said frame, said toggle mechanism having amovable arm, a switch contact point carried by said movable arm, astationary juxtaposed companion switch contact point carried within saidcontainer whereby predetermined rotation speeds of said driving rotorcauses said movable arm to close and open said contact points, and meansfor changing the position of said stationary contact '8 relative to thecontact carried by said arm to change the responsive speed at which thecontacts open.

References Cited in the file of this patent UNITED STATES PATENTS1,677,008 Townsend July 10, 1928 2,279,999 McKechnie Apr. 14, 19422,518,478 Kohl Aug. 15, 1950 2,558,223 Roger June 26, 1951 FOREIGNPATENTS 591,320 Great Britain Aug. 14, 1947

